They might, but why should they have to? That tiny ESS DAC in LG phones is measurably better than a lot of external "audiophile-grade" DACs. It doesn't compromise the design or the water resistance of the phone either and probably doesn't add much cost relative to other components.

This is basically an arrogant move that can't really be technically justified. E.g. By arguing that better external options exist - better external cameras also exist, should we get rid of the camera too?